In recent years, there is known torque fuse control that controls engagement pressure of a clutch arranged in series with a belt-type CVT (automatic transmission) so that the clutch is slipped before the CVT belt is slipped, thereby preventing excessive torque from being transmitted to the belt, as taught, for example, by a Patent Reference 1. In a technique of the Patent Reference 1, a lockup clutch is used as the clutch and its engagement pressure is increased and decreased with time.